In servicing electronic equipment of all kinds, two primary diagnostic tools are indispensable: the oscilloscope for observing the waveforms of electronic circuits under dynamic conditions and the multimeter for checking voltages, currents, resistances, et cetera, throughout the circuitry. Miniature solid-state oscilloscopes are now available, providing both versatility and portability. Miniature multimeters are also available which utilize digital processing means to provide extremely accurate measurement readings.
In one attempt to marry the digital multimeter with the oscilloscope, a multimeter plug-in module was designed for use with a sophisticated laboratory oscilloscope having extremely limited portability. Such laboratory oscilloscopes generally have at least two plug-in compartments for the vertical channels, and an additional plug-in compartment to accept a time-base plug-in module. Because of the nature of such oscilloscopes, circuitry must be separated into various plug-in modules, resulting in duplication of many circuits.